Platinum/mesoporous WO₃ as a carbon-free electrocatalyst with enhanced electrochemical activity for methanol oxidation

A new type of carbon-free electrode catalyst, Pt/mesoporous WO₃ composite, has been prepared and its electrochemical activity for memanol oxidation has been investigated. The mesoporous tungsten trioxide support was synthesized by a replicating route and the mesoporous composties with Pt loaded were characterized by using X-ray diffraction (XRD), nitrogen sorption, field emission scanning electron microscopy (FE-SrZM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. Cyclic voltammetry (CV), line scan voltammetry (LSV) and chronoamperometry (CA) were adopted to characterize the electrochemical activities of the composites. The mesoporous WO₃ showed high surface area, ordered pore structure, and nanosized wall dhickness of about 6-7 nm. When a certain amount of Pt nanoparticles were dispersed in the pore structure of mesoporous WO₃, the resultant mesostructured Pt/WO₃ composites exhibit high electro-catalytic activity toward memanol oxidation. The overall electro-catalytic activities of 20 wt % Pt/WO₃ composites are significantly higher than mat of commercial 20 wt % Pt/C catalyst and are comparable to the 20 wt % PtRu/C catalyst in me potential region of 0.5-0.7 V. The enhanced electrocatalytic activity is attributed to be resulted from the assistant catalytic effect and the mesoporous structure of WO₃ supports.